Connect your huawei to pc go to settings and change type connection from auto to 4G only

Try to update your firmware from this link : http://www.tp-link.com/lk/download/TL-MR3020.html#Firmware if it was not working try to contact TP-Link technical support.

Before buy you should sure of supporting your usb dongle.If your usb dongle have a linux driver maybe you can do something.Contact to the TP-Link support technical

Are you sure your 3G dongle is healthy ?Check it without router on your pc or laptop. If it was work fine then go to the TP-Link services

Maybe you can do this from your 3G usb stick settings and change connection type from auto to HSDPA

Model : TL-MR3420 Hardware Version : MR3420 v2 00000000 Firmware Version : 3.13.27 Build 121206 Rel.60215n ISP : Hi I have 3G/4G Wireless N Router Model No. TL-MR3420 I want to connect to internet to...